title: Lack of functional GABAB receptors alters Kiss1 , Gnrh1 and Gad1 mRNA expression in the medial basal hypothalamus at postnatal day 4.
abstract: OBJECTIVE
  Adult mice lacking functional GABAB receptors (GABAB1KO) show altered Gnrh1 and Gad1 expressions in the preoptic area-anterior hypothalamus (POA-AH) and females display disruption of cyclicity and fertility. Here we addressed whether sexual differentiation of the brain and the proper wiring of the GnRH and kisspeptin systems were already disturbed in postnatal day 4 (PND4) GABAB1KO mice.
  
  
  METHODS
  PND4 wild-type (WT) and GABAB1KO mice of both sexes were sacrificed; tissues were collected to determine mRNA expression (qPCR), amino acids (HPLC), and hormones (RIA and/or IHC).
  
  
  RESULTS
  GnRH neuron number (IHC) did not differ among groups in olfactory bulbs or OVLT-POA. Gnrh1 mRNA (qPCR) in POA-AH was similar among groups. Gnrh1 mRNA in medial basal hypothalamus (MBH) was similar in WTs but was increased in GABAB1KO females compared to GABAB1KO males. Hypothalamic GnRH (RIA) was sexually different in WTs (males > females), but this sex difference was lost in GABAB1KOs; the same pattern was observed when analyzing only the MBH, but not in the POA-AH. Arcuate nucleus Kiss1 mRNA (micropunch-qPCR) was higher in WT females than in WT males and GABAB1KO females. Gad1 mRNA in MBH was increased in GABAB1KO females compared to GABAB1KO males. Serum LH and gonadal estradiol content were also increased in GABAB1KOs.
  
  
  CONCLUSIONS
  We demonstrate that GABABRs participate in the sexual differentiation of the ARC/MBH, because sex differences in several reproductive genes, such as Gad1, Kiss1 and Gnrh1, are critically disturbed in GABAB1KO mice at PND4, probably altering the organization and development of neural circuits governing the reproductive axis.
authors.affiliation: Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina.
authors.forename: Noelia P
authors.initials: NP
authors.lastname: Di Giorgio
authors.forename: Paolo N
authors.initials: PN
authors.lastname: Catalano
authors.forename: Paula V
authors.initials: PV
authors.lastname: López
authors.forename: Betina
authors.initials: B
authors.lastname: González
authors.forename: Sheila J
authors.initials: SJ
authors.lastname: Semaan
authors.forename: Gabriela C
authors.initials: GC
authors.lastname: López
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Kauffman
authors.forename: Susana B
authors.initials: SB
authors.lastname: Rulli
authors.forename: Gustavo M
authors.initials: GM
authors.lastname: Somoza
authors.forename: Bernhard
authors.initials: B
authors.lastname: Bettler
authors.forename: Carlos
authors.initials: C
authors.lastname: Libertun
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Lux-Lantos
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001111:Arcuate Nucleus of Hypothalamus / Q000254:growth & development / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005968:Glutamate Decarboxylase / Q000172:deficiency* / Q000235:genetics; D007987:Gonadotropin-Releasing Hormone / Q000172:deficiency* / Q000235:genetics; D007033:Hypothalamus, Middle / Q000254:growth & development / Q000378:metabolism*; D059648:Kisspeptins / Q000172:deficiency* / Q000235:genetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D011498:Protein Precursors / Q000172:deficiency* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018080:Receptors, GABA-B / Q000172:deficiency* / Q000235:genetics; D012733:Sex Differentiation / Q000235:genetics*
chemical_list: C491407:Kiss1 protein, mouse; D059648:Kisspeptins; D011498:Protein Precursors; D012333:RNA, Messenger; D018080:Receptors, GABA-B; C050866:progonadoliberin I; D007987:Gonadotropin-Releasing Hormone; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1